Spas, such as portable spas, typically accommodate four to twelve individuals and are usually stand-alone upright structures in which a water reservoir, plumbing and controls are housed within a cabinet for forming a single self-contained unit. Portable spas are popular as they can be located at virtually every home. Spas are typically installed outdoors and can be used all year round, including in winter freezing conditions and at elevated summer temperatures. Particularly for use at sub-zero conditions, water in the water reservoir or spa vessel is typically maintained at a temperature slightly above body temperature (such as about 103° F.). To date, the water in the spa vessel is typically heated by flowing the water through a heating device, such as being pumped through a compressor-based flow-through heat pump or by directly contacting the water with a submersed resistive heating element. A removable insulated spa cover, positioned to cover the temperature controlled water, minimizes heat losses from the water during periods of low ambient temperature and non-use.
Applicant has, for some time, utilized an insulated cabinet for supporting the spa vessel therein. The insulated cabinet retains heat in an air space formed about the spa vessel between the insulated cabinet and the spa vessel. Motors, heaters, controllers and other plumbing equipment are typically located in this air space. In cooler seasons, significant energy savings are achieved by retaining the heat in the warm air space between the spa vessel and the insulated cabinet. Unfortunately, as the outside environment becomes warmer, the air space can become too hot for the spa equipment or components resident therein.
To date, hot air from the air space has been passively managed through inherent heat loss from the cabinet and imperfect sealing of the air space. One convenient break in the otherwise sealed, insulated cabinet has been the removable access panels provided in the cabinet. The access panels have not been tightly sealed to the cabinet and permit some infiltration and ex-filtration of ambient air. This crude methodology has resulted in sufficient heat loss to protect components during hot seasons, but has also resulted in unmanaged and reduced efficiency during cooler seasons.
There is interest in apparatus and methods for cooling the air space in a controlled manner without compromising efficiency and without risk to the components resident in the air space.